--- In harryproa@..., "Mark Stephens" <stephens@o...>
wrote:
> I agree, I think slippage would be easily overcome with driven
rollers
> on either side of the board. Could always roughen the board a bit. I
> don't think there would be much downward load once the board has
jammed
> itself in the case with side and fore/aft loads. The problem I see
is
> the rollers jamming the board forward or backwards into the case as
they
> tried to roll around the sectional curve.

I was thinking of rollers at the leading end of the blades and the
driving rollers on the relatively flat section aof the foil. this
would allow pressure on the drive rollers to be controlled with very
small movement of the forward rollers. Still the difficulty of
transferring power smoothly and controllably through endless rope
systems to a point so far from the centre pivot I can imagine is not
easy. pulley sytems have to be centred exactly on the rudder axis and
have zero diameter or the blades will rise and fall as the rudder is
turned and frictional losses and rope stretch exacerbate control.
Still, a little rise and fall may not be too much price to pay.
Electric in some ways seems easier and may end up cheaper.
Robert



Also turning the rollers in
> opposite directions driven with an endless line is easy to say but
not
> so easy to do simply.
>
> Visionarry is coming along nicely with the owner working on it full
time
> now. The decks are painted, s/s fittings on, plumbing complete,
wiring
> done. I've been doing the odd day here and there and today started
on
> the interior wood trimming. She's looking fabulous. Should be
launched
> within the next few weeks though don't hold me to it. She won't
have a
> rig but even motoring should be a blast.
>
> I'll see if I can get Michele to put some pics on the website.
>
> Bain's Harry is also progressing. It's mostly built and faired with
> steering details the next step. Not game to mention a launch date.
>
Thanks for the update, regards to all at Urunga

Robert




>
> Mark
>
>